Impulse SCM5B43 - Manual

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Isolated Analog Signal Conditioning Products SCM5B
SCM5B43
General Purpose Input Modules, with DC Excitation
Description
Each SCM5B43 general purpose input module provides a single channel of
transducer input which is filtered, isolated, scaled, and converted to a high level
analog voltage output (Figure 1). This voltage output is logic switch controlled,
which allows these modules to share a common analog bus without the
requirement of external multiplexers.
The SCM5B modules are designed with a completely isolated computer side
circuit which can be floated to ±50V from Power Common, pin 16. This complete
isolation means that no connection is required between I/O Common and Power
Common for proper operation of the output switch. If desired, the output switch
can be turned on continuously by simply connecting pin 22, the Read-Enable
pin, to I/O Common, pin 19.
The SCM5B43 can interface to devices which require a precision 10VDC
excitation supply. The 1kHz bandwidth significantly reduces ripple and noise
inherent in these devices.
Transducer excitation is provided from the module by a very stable 10V source.
The excitation supply is fully isolated, allowing the amplifier inputs to operate over
the full range of the excitation voltage. This feature offers significant flexibility in
real world applications. Eight full scale input ranges are provided, from ±1V to
±10V, producing ±5V full scale output.
The input signal is processed through a pre-amplifier on the field side of the
isolation barrier. This pre-amplifier has a gain-bandwidth product of 5MHz and
is bandwidth limited to 1kHz. After amplification, the input signal is chopped by
a proprietary chopper circuit. Isolation is provided by transformer coupling,
again using a proprietary technique to suppress transmission of common mode
spikes or surges. The module is powered from +5VDC, ±5%.
Special input circuits on the SCM5B43 module provide protection of the signal
inputs and the isolated excitation supply up to 240VAC.
Figure 1: SCM5B43 Block Diagram
Features
• Interfaces to DC Displacement Transducers
and Other Devices Requiring a Stable DC
Supply
• High Level Voltage Outputs
• 1500Vrms Transformer Isolation
• ANSI/IEEE C37.90.1 Transient Protection
• Input Protected to 240VAC Continuous
• Fully Isolated Excitation Supply
• 100dB CMR
• 1kHz Signal Bandwidth
• ±0.03% Accuracy
• ±0.005% Linearity
• ±20µV/°C Drift
• CSA Certified, FM Approved, CE and ATEX
Compliant
• Mix and Match SCM5B Types on Backpanel
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